This invention generally relates to printers and printer methods and more particularly relates to a printer capable of forming an image on a receiver substrate according to type of receiver substrate, and a method of assembling the printer.
Digital prepress color proofing is an example of a printing application in which there are significant demands for accuracy in representation of images. In digital prepress color proofing, the goal is to produce a xe2x80x9cproof sheetxe2x80x9d that will resemble as closely as possible the final output of a color printing system (e.g., an offset color printer). This requires that the proof sheet match both expected color reproduction as well as xe2x80x9clook and feelxe2x80x9d of the receiver substrate. The more accurately a prepress proofing system reproduces paper thickness, weight, color, gloss, and other characteristics in the color proof, the better the system will provide final output prints that meet customer expectations.
Color proofing devices are known. A laser thermal printer having color proofing capability is disclosed in commonly assigned U.S. Pat. No. 5,268,708 titled xe2x80x9cLaser Thermal Printer With An Automatic Material Supplyxe2x80x9d issued Dec. 7, 1993 in the name of R. Jack Harshbarger, et al. The Harshbarger, et al. device is capable of producing a proof on a number of different paper stocks that differ by weight, gloss, color, and other characteristics. For a high-quality imaging system such as is disclosed in the Harshbarger, et al. patent, it is possible to vary specific parameters in the printing process in order to achieve a desired result.
According to the Harshbarger, et al. patent, a printer accepts a rasterized image from a prepress workstation and a printer device prints this raster image, with the necessary color density, onto an intermediate receiver. This intermediate receiver holds the image in reversed or xe2x80x9cmirroredxe2x80x9d form. The intermediate receiver is ultimately used to transfer an image onto a preconditioned, prelaminated paper substrate. In this regard, a prelamination procedure, performed using a laminator apparatus, is used to precondition the paper substrate for printing by applying a thin layer of laminate material onto the surface of the paper substrate. This prelamination procedure conditions the surface of the paper substrate for accepting the image transferred from the intermediate receiver, allowing a predictable and accurate response to colorant levels. When a sheet of paper substrate is thus prepared, an image is then transferred from the intermediate receiver using the laminator apparatus to provide appropriate levels of heat and pressure as it presses the intermediate receiver against the preconditioned paper substrate. The image is thus transferred to the sheet of paper substrate. It should be noted that this image transfer operation is carried out completely inside the laser thermal printer disclosed in the Harshbarger, et al. patent.
It is known that one of the key parameters that can be varied by a laser thermal printer, whether transferring colorant directly to the paper substrate or first to an intermediate receiver, is colorant density. Density can be controlled within a specified range of values by varying the exposure energy levels applied, which in turn determines the amount of colorant transferred by a marking apparatus during the printing process. By varying exposure energy applied to create the image on an intermediate receiver, a laser thermal printer can emulate the actual printing performance of an offset color press or other printers when using paper substrates having certain characteristics. Similarly, an inkjet printer or electrophotographic printer can be adjusted so as to emulate color press output, by varying the amount of colorant applied or by adjusting operational variables such as drying time or fusing temperature and speed. In any event, chief among the characteristics of the paper substrate is the color of the paper substrate, which serves as a background for the printed image. However, paper substrates can vary widely in color content, ranging from a bright white color that is typical of photographic papers, to duller colors such as are typical of newsprint papers. In order to adjust printer exposure to correctly compensate for paper color, an operator using a digital prepress proofing system makes densitometer measurements of paper color content prior to printing. Such measurements provide values that can be used to calculate an appropriate amount of compensation in printer exposure (or in other operational variables) for a given type of paper substrate. However, the need for the operator to make densitometer measurements of paper color content prior to printing is time-consuming, prone to operator error and therefore costly. Hence, a problem in the art is increased costs due to the need for the operator to make densitometer measurements of paper color content prior to printing.
The densitometer measurements mentioned hereinabove are used to calibrate the printer. In other words, for the system disclosed in the Harshbarger, et al. patent, initial compensation for paper characteristics is based on measurements taken as a part of overall system calibration. In the process for calibrating the printer located at a specific site, the RGB density of a paper type typically used at that site is measured using a densitometer. Then, in modeling colorant density versus exposure for a printer, the density of the underlying paper substrate is subtracted from colorant density measurements. It should be noted that this procedure provides a workable estimate for making calibration adjustments. However, if a site uses two or more papers that vary widely in color characteristics, some compromise in calibration strategy must then be used. Therefore, another problem in the art is the need to compromise calibration strategy if a site uses two or more papers that vary widely in color characteristics.
Additional compensation for paper substrate characteristics is provided by dot-gain profiles used with prior art prepress proofing systems, such as the system disclosed in the Harshbarger, et al. patent. A dot-gain profile models the real-world behavior of offset color printing inks when applied to paper at various values of halftone screen, where there is typically some amount of xe2x80x9cgainxe2x80x9d in the nominal dot size based on ink spreading and other factors. The Harshbarger, et al. device allows an operator to set-up and use a number of different dot-gain profiles, based on factors such as the specific press being emulated, the specific paper being used, and the specific screen size being employed. Based on the dot-gain profile selected, and a predetermined target density, the printer adjusts dot characteristics and exposure when creating the image on the intermediate receiver in order to emulate the real-world behavior of ink on paper substrate. In order to use dot-gain profiles effectively, an operator must know, in advance, details about the paper that will be used for the proof and, ultimately, for the print job. Therefore, another problem in the art is pre-knowledge the operator must acquire concerning details about paper properties that will be used in making the proof.
Still other compensation for paper substrate characteristics can be applied during other phases of the imaging process. For example, with the system disclosed in the Harshbarger, et al. patent, the prelaminate material itself can have characteristics that affect the color of the paper substrate. Additionally, the colorant transfer process, in which the image is transferred from an intermediate receiver onto the paper substrate, requires adjustment to compensate for paper characteristics. An apparatus designed for colorant transfer must typically vary heat, pressure, and contact time to control the effectiveness of colorant transfer, affecting the density of the final printed image. Hence, another problem in the art is need for the operator to ascertain how the prelaminate material will affect color of the paper and the need for the operator to ascertain how to vary heat, pressure, and contact time to control the effectiveness of colorant transfer which affects density of the final printed image.
Therefore, whether a printer prints directly to paper, as for example in some types of laser thermal printers, inkjet printers, and electrophotographic printers, or uses a transfer process by first printing to an intermediate receiver, such as with the system disclosed in the Harshbarger, et al. patent, there can be significant benefit in sensing characteristics of the paper substrate that will ultimately receive the final printed image. As previously mentioned, while existing prior art methods may provide some level of compensation for paper substrate properties in the printing process, there are drawbacks. As previously mentioned, with the system disclosed in the Harshbarger, et al. patent, the printer apparatus does not write directly to the paper substrate. To properly xe2x80x9ctunexe2x80x9d the writing operation, it is required that the operator correctly identify the paper substrate type to be ultimately used and employ the correct dot-gain profile that has been designed for that particular type of paper substrate. As stated hereinabove, the operator must manually make adjustments to the laminator apparatus that performs colorant transfer, in order to set speed, pressure and temperature. There is risk of operator error, because these processes require judgment and care when setting-up the printing apparatus to run a proof print.
In addition, the printer disclosed in the Harshbarger et al. patent uses a single laminator apparatus to perform both lamination and image transfer functions. Use of a single device for lamination and image transfer is most readily feasible when lamination material is in sheet form. Also, use of a single device for laminatin and image transfer is most readily feasible when the laminatin material is in powder form, which occurs, for example, when the laminate is a fine powder similar to toner used in electrophotographic imaging. However, use of a single device for lamination is inappropriate when the laminate is in liquid form.
With other types of printers, an operator may be able to make some type of adjustment based on the paper to be used, such as varying colorant quantity, drying time, fusing time, and fusing temperature. However, correctly making this type of manual adjustment likewise requires a high level of skill and judgment on the part of the printer operator, thereby increasing risk of operator error.
There can also be significant information required about a paper substrate in addition to its color, when such information might be useful in adjusting printer operating parameters. Information regarding variables such as paper surface gloss, thickness, age, grain direction, manufacturer""s name, density, and other parameters could be used to adjust a printer for improved performance.
Prepress proofing printers have been adapted to identify types of intermediate media loaded within the printer. A commonly assigned, copending application that provides apparatus for sensing intermediate media in a printer is U.S. Ser. No. 09/133,114 filed Aug. 12, 1998 and titled xe2x80x9cA PRINTER WITH MEDIA SUPPLY SPOOL ADAPTED TO SENSE TYPE OF MEDIA, AND METHOD OF ASSEMBLING SAMExe2x80x9d. Here, the receiver media resides on a spool within the printer and a memory is integrally attached to an RF transponder attached to the spool. The memory stores identifying information concerning a property of the receiver media. The receiver media spool and attached memory are actually loaded inside the marking engine portion of the printer.
Another commonly assigned, copending application that provides apparatus for sensing intermediate media in a printer is U.S. Ser. No. 09/281,595 filed Dec. 22, 1998 and titled xe2x80x9cA PRINTER WITH DONOR AND RECEIVER MEDIA SUPPLY TRAYS EACH ADAPTED TO ALLOW A PRINTER TO SENSE TYPE OF MEDIA THEREIN, AND METHOD OF ASSEMBLING THE PRINTER AND TRAYSxe2x80x9d. Here, the receiver media resides in a supply tray within the printer and a memory is integrally attached to an RF transponder attached to the supply tray. The memory stores identifying information concerning a property of the receiver media residing in the supply tray. The supply tray and attached memory are actually loaded inside the marking engine portion of the printer.
Although U.S. Ser. No. 09/133,114 and U.S. Ser. No. 09/281,595 both disclose use of a memory integrally attached to an RF transponder coupled to receiver media, where the memory stores identifying information about a receiver media property, both of these devices use a memory attached to the receiver media that are actually loaded inside the marking engine portion of the printer. However, with prepress proofing systems, the paper substrate itself may not be loaded in the marking engine, but can receive the image in a separate, subsequent transfer operation. In this subsequent transfer operation, the receiver media serves as an intermediate from which the image is transferred onto the paper substrate. Moreover, the paper substrate itself can be preconditioned, such as by lamination, prior to transfer of the image to the paper substrate. Preconditioning methods and materials can alter surface characteristics of the paper substrate and can affect how the paper substrate responds to the image transfer process, as previously mentioned. For example, a paper substrate from a specific manufactured batch can exhibit different surface characteristics depending on type of prelaminate or how a prelaminate layer is applied. That is, the prelaminate can be applied under various temperature or timing settings. Moreover, color density of a paper that has been preconditioned by lamination can vary, depending on the laminate material used. In light of these differences, the apparatus disclosed in the Ser. No. 09/133,114 and Ser. No. 09/281,595 copending applications do not appear to provide a solution suited to accommodate variable preconditioning of a paper receiver substrate. Therefore, yet another problem in the art is the need to accommodate variable preconditioning required for a paper receiver substrate.
In addition, attachment of a memory to a paper tray, as disclosed in the Ser. No. 09/281,595 copending application, may not be practical or necessary in all cases and may increase cost of printer media as well as printer hardware. In cases where it is only necessary to identify a specific paper, donor, receiver, or laminate material type, use of a memory may not be needed. Other methods for identifying specific paper type and other properties can be used with less expense and complexity. On the other hand, in a case where a substantial amount of information is needed, memory may be a constraint. In such a case, use of a highly structured memory, such as disclosed in the Ser. No. 09/281,595 copending application, can limit the amount of information available from a paper substrate manufacturer. Solutions proposed in the Ser. No. 09/281,595 and the Ser. No. 09/133,114 copending applications may not easily lend themselves to changes when manufacturers want to add other information to an attached memory. Additionally, it may not be practical for an attached memory to store all possible information describing interactions of a specific paper and a specific preconditioning laminate. For example, media types may have many different manufacture dates. Also, although a manufacturer may be able to provide known information on how different types of media interact in a specific case simply by providing batch numbers and types for a paper substrate and a laminate material at time of manufacture, the solutions noted hereinabove provide no method for obtaining updated and current data on media interaction directly from a manufacturer where such current information would only be available subsequent to the date of manufacture. Thus, another problem in the art is need to obtain current data on media interaction directly from a manufacturer where such information would only be available subsequent to the date of manufacture.
Thus, there has been a long-felt need to provide a printer capable of forming an image on a receiver substrate according to type of receiver substrate, and a method of assembling the printer, in order to detect properties of the receiver substrate, so that preconditioning that has been performed on the receiver substrate is determinable in order to enable the printer to automatically adjust printing operation.
It is an object of the present invention to provide a printer capable of forming an image on a receiver substrate according to type of receiver substrate, and method of assembling the printer in order to detect properties of the receiver substrate, so that any preconditioning that has been performed on the receiver substrate enables the printer to automatically adjust printing operation accordingly.
With the above object in view, the present invention resides in a printer capable of forming an image on a receiver substrate according to type of receiver substrate, comprising an identifier coupled to the receiver substrate, the identifier containing identifying information uniquely associated with the type of receiver substrate; a sensor disposed in sensing relation to the identifier for sensing the identifying information, so that the type of receiver substrate is identified as the sensor senses the identifying information; and an image marker coupled to the sensor for forming the image on the receiver substrate according to the identifying information sensed by the sensor.
According to an exemplary embodiment of the present invention, the sensor comprises a transceiver capable of transmitting a first electromagnetic field and capable of sensing a second electromagnetic field characteristic of the identifying information. The identifier comprises a transponder capable of receiving the first electromagnetic field transmitted by the transceiver. The first electromagnetic field powers the transponder, which then generates the second electromagnetic field. The second electromagnetic field, characteristic of the identifying information, is sensed by the transceiver. The image marker, which is coupled to the transceiver, forms the image on the receiver substrate according to the identifying information sensed by the transceiver.
According to another exemplary embodiment of the present invention, the sensor comprises a transceiver capable of transmitting a first electromagnetic field containing identifying information concerning the receiver substrate. The identifier comprises a transponder capable of receiving the first electromagnetic field transmitted by the transceiver and storing the identifying information in the transponder for subsequent use. This embodiment of the present invention allows previously stored identifying information that may be residing in the transponder to be updated with different identifying information.
A feature of the present invention is the provision of a transceiver for transmitting a first electromagnetic field to power a transponder which in turn generates a second electromagnetic field characteristic of identifying information associated with a property of the receiver substrate for printing a proof according to the property of the receiver substrate.
Another feature of the present invention is the provision of a transceiver to address a transponder coupled to a receiver substrate and to write identifying information to that transponder, where the data written is indicative of a property of the receiver substrate.
Still another feature of the present invention is the provision of an identifier coupled to a laminate material used to precondition the receiver substrate for printing a proof sheet according to a property of the laminate material.
An advantage of the present invention that use thereof obviates need for manual entry of data describing a receiver substrate. That is, the invention is capable of providing information to an operator or to the printer apparatus itself describing a receiver substrate that is to be used in the printer apparatus.
Another advantage of the present invention that use thereof provides a contactless communication interface, accessing data without requiring that electrical contact be made to corresponding contacts mounted on a receiver substrate supply or in contact with a laminate material supply.
Yet another advantage of the present invention that use thereof allows backward-compatibility with existing receiver substrate supply designs for printers. That is, receiver substrate provided with transponder components can be used in older printers that may not be equipped with the necessary transceiver and logic circuitry that enable use and management of data concerning the receiver substrate. No substantial alteration of external packaging is necessary to implement this invention.
A further advantage of the present invention that, using a networked configuration, it allows a printer to access and use manufacturer information and updates on media properties, when this information becomes available after the manufacturing date of the media.
These and other objects, features, and advantages of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings wherein there are shown and described illustrative embodiments of the invention.